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Unit 1 Day 7

Similarity continued

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Warm UpGiven triangle CDE with C(2, 2), D(-6, 4) and E(-2, -6), write the points of the image under the following transformations. For #1 and 2, write the description and the vertices. For #3 and 4, give the algebraic rule and the coordinate pairs.

Enlargement by scale factor of 3.

C’(6, 6), D’(-18, 12), E’(-6, -18)

Reduction by a factor ¼.

C’(1/2, 1/2), D’(-3/2, 1), E’(-1/2, -3/2)

C’(2/3, 2/3), D’(-2, 4/3), E’(-2/3, -2)

(x, y) (1/3x, 1/3y)

1) , 3 ,3

1 12) , ,

4 4

x y x y

x y x y

3) Dilation with a scale factor 2

4) Horizontal shrink with scale factor of 1/3, vertical shrink

with a scale factor 1/3

5) Do you agree or disagree with Logan? Explain your reasoning.

Disagree! There is no common scale factor

(x, y) (2x, 2y)C’(4, 4), D’(-12, 8), E’(-4, -12)

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Day 6 Homework

∆RVW by AA~ ∆ JST by AA~

x = 52

x = 40

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Day 6 Homework Continued

∆ELM SAS~

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Day 6 Homework Continued

x = 6

y = -9

24, 30, 126

x = 3

y = -8

20, 10, 150

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Day 6 Homework Continued

Translation 2 right and 3 down

(x, y) (x + 2, y – 3)

Dilation by scale factor 2

(x, y) (2x, 2y)

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Day 6 Homework Continued

Dilation by scale factor 2 AND 180° rotation(or reflect across both axes)

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Day 6 Homework Continued

Translation down 5 AND 90° rotation

(x, y) -> (-y + 5, x)

Reflected over x-axis, dilated by ½

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Day 6 Homework Continued

for first part

overall

(x, y) (x + 2, y + 4)

(x, y) (-2x, 2y)

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Tonight’s HomeworkPages 23 – 24 ALL

Pages 13 – 14 ODDS (this IS back in the first part of the packet, the part we gave you!)

Print Out Third Portion of Unit One Homework by Tomorrow (bring both printed packets to class from Blackboard)!

*Packet Days 8-13

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Same Type of Figures

Similar Figures

Congruent Figures

Figures with the same shape, but of a proportional size.

All angle pairs are congruentAll side pairs are proportional

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Foundational PracticeAre the polygons similar?? If so, write a similarity

statement.

Given A E and C G, are the polygons similar?? If so, explain why, write a similarity statement, and find x.

Ð Ð ÐÐ

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5=

12

6=

14

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By: SSS ~

AA~

SAS~

By: AA~ 6

x=

5

3.3

x = 3.96

∆ABC ~ ∆XYZ

∆CAB ~ ∆GEF

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Foundational Practice Continued…Explain why the triangles are similar and write a similarity statement.

2

4=

4

8 By: SAS ~

By: AA ~

∆ABX ~ ∆RQX

∆QMP ~ ∆AMB

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A Tough one….Let’s try this together!

Explain why the triangles are similar and write a similarity statement. Then, solve for the variable, where appropriate.

3 4

8 x

∆ACD ~ ∆ABE

By: AA ~

4

x

5

3

A

C D

B E

x = 32/3 or 10 2/3

Be careful! Drawing the small

triangle separately can help!

Do full side full side

full side full side

←Remember to read

the problem!!

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Some Word Problems

6 9 6

6 9 6

4

xO

t

Rx

x f

8 4 8

2 4 2

4

xO

t

Rx

x f

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You Try!

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You Try Answers!

3 18 3

18 54 54

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xOR

x

x cm

4 12 4 21

21 12

63x

O

m

Rx x

k

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You Try Answers!

2 10 2 6

6 10

30x miles

ORx x

12 8 12 15

15 8

10x

O

t

Rx x

f

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Practice: Similar Figures

Notes p.27 - 28

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Page 27 Solutions

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Page 27 Solutions Continued.. ‘Notes Packet’

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Page 28 Solutions ‘Notes Packet’

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Page 28 Solutions Continued.. ‘Notes Packet’

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Kahoot!!

• https://play.kahoot.it/#/?quizId=e0bfb771-bf4a-402b-a409-8548c6b92df6

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Tonight’s HomeworkPages 23 – 24 ALL

Pages 13 – 14 ODDS (this IS back in the first part of the packet, the part we gave you!)

Print Out Third Portion of Unit One Homework by Tomorrow (bring both printed packets to class from Blackboard)!

*Packet Days 8-13